- Structural characterization of a new cobalt(II) complex of 1-benzyl-5-methyl-1H-imidazole
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The preparation of a cobalt(II) chloride complex with a N-donor ligand 1-benzyl-5-methyl-1H-imidazole of formula [CoCl2(1-benzyl-5-methyl-1H-imidazole)2] is described. The isolated complex was characterized by UV, IR spectroscopy and crystallographic studies. Single crystal X-ray diffraction analysis of the complex reveals its monomeric tetra-coordinated nature. The coordination polyhedron around the cobalt center can be described as a quasi-regular tetrahedron. The Co–N distances for this compound are 2.0111(17) ? and 2.0118(17) ?, while the Co–Cl distances are 2.2582(7) ? and 2.2549(7) ?. The crystal packing can be described as layers parallel to (101) plane alternating along the b axis, and it is stabilized by π–π stacking between the imidazole and phenyl rings. The shortest centroid–centroid distance is 3.6002(14) ?.
- Bouchouit,Bouraiou,Bouacida,Belfaitah,Merazig
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- N-Substituted acetamidines and 2-methylimidazole derivatives as selective inhibitors of neuronal nitric oxide synthase
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A series of N-substituted acetamidines and 2-methylimidazole derivatives structurally related to W1400 were synthesized and evaluated as Nitric Oxide Synthase (NOS) inhibitors. Analogs with sterically hindering isopropyl and phenyl substituents on the benzylic carbon connecting the aromatic core of W1400 to the acetamidine nitrogen, showed good inhibitory potency for nNOS (IC 50= 0.2 and 0.3 μM) and selectivity over eNOS (500 and 1166) and to a lesser extent over iNOS (50 and 100). A molecular modeling study allowed to shed light on the effects of the structural modifications on the selectivity of the designed inhibitors toward the different NOS isoforms.
- MacCallini, Cristina,Patruno, Antonia,Lannutti, Fabio,Ammazzalorso, Alessandra,De Filippis, Barbara,Fantacuzzi, Marialuigia,Franceschelli, Sara,Giampietro, Letizia,Masella, Simona,Felaco, Mario,Re, Nazzareno,Amoroso, Rosa
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- Atom Transfer Radical Polymerization-Inspired Room Temperature (sp3)C-N Coupling
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A simple nonphotochemical procedure is reported for Cu(I)-catalyzed C-N coupling of aliphatic halides with amines and amides. The process is loosely based on the Goldberg reaction but takes place readily at room temperature. It uses Cu(I)Br, a commonly used and inexpensive atom transfer radical polymerization precatalyst, along with the cheap ligand N,N,N′,N″,N″-pentamethyldiethylenetriamine, to activate the R-X bond of the substrate via inner-sphere electron transfer. The procedure brings about productive C-N bond formation between a range of alkyl halide substrates with heterocyclic aromatic amines and amides. The mechanism of the coupling step, which was elucidated through application of computational methods, proceeds via a unique Cu(I) → Cu(II) → Cu(III) → Cu(I) catalytic cycle, involving (a) inner-sphere electron transfer from Cu(I) to the alkyl halide to generate the alkyl radical; (b) successive coordination of the N-nucleophile and the radical to Cu(II); and finally reductive elimination. In the absence of a nucleophile, debrominative homocoupling of the alkyl halide occurs. Control experiments rule out SN-type mechanisms for C-N bond formation.
- Coote, Michelle L.,Fung, Alfred. K. K.,Sherburn, Michael S.,Yu, Li-Juan
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p. 9723 - 9732
(2021/07/20)
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- Imidazole-Bridged Tetrameric Group(IV) Heteroleptic Complexes from the Spontaneous Metal-Ligand Assembly of a Potentially N4-Tetradentate Ligand
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The imidazole-containing N4-tetradentate ligand N-(2-(1H-imidazol-2-yl)-3-(pyridin-2-yl)propyl)-2,6-diisopropylaniline (L2H) and its N-benzyl-protected variant (L2Bn) at the imidazole fragment have been synthesized and fully characterized. Both molecules contain an unresolved Csp3 stereogenic center. The coordination behavior of the newly prepared ligands towards group IV metal ions (MIV = Zr, Hf) has been examined through multinuclear 1H and 13C{1H} NMR spectroscopy and selected single-crystal X-ray structural analyses. The ability of the imidazole fragment to enter the metal coordination sphere as a neutral or a monoanionic system has also been investigated, unveiling quite original coordination modes as well as unexpected molecular architectures. When one N imidazole atom is blocked by a benzyl protecting group (L2Bn), the ligand reaction with MIV(NMe2)4 (MIV = Zr, Hf) as metal precursor gives rise to discrete monometallic tris(dimethylamido) 5-coordinated compounds of general formula L2BnM(NMe2)3. The ligand chelates the metal ion as a bidentate monoanionic κ2{N–,N} system through the imidazole moiety and the anilido N donor while an uncoordinated picolyl arm dangles away from the metal center. Upon coordination to the metal ion, the unprotected L2H undergoes a unique self-assembly of the chiral racemic ligand to generate an achiral tetrameric network featuring a regularly alternating (R*,S*,R*,S*) configuration around the 6-coordinated metal centers. The resulting bis(dimethylamido) tetrameric architectures of formula [L2HM(NMe2)2]4 named “poker complexes” contain the imidazole fragment of each ligand bridging two adjacent MIV ions in a μ-κ{N}:κ{N–} coordination hapticity. At the same time, the picolyl fragments of each chelating L2H ligand “sting” a neighboring metal center as unconventional scorpion's tails that impose further rigidity to the tetrameric structure.
- Luconi, Lapo,Tuci, Giulia,Yakhvarov, Dmitry,Poli, Giovanni,Rossin, Andrea,Khusnuriyalova, Aliya,Giambastiani, Giuliano
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p. 4384 - 4393
(2019/09/17)
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- Synthesis and investigation of inhibitory activities of imidazole derivatives against the metallo-β-lactamase IMP-1
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Mutations in bacteria can result in antibiotic resistance due to the overuse or abuse of β-lactam antibiotics. One strategy which bacteria can become resistance toward antibiotics is secreting of metallo β-lactamase enzymes that can open the lactam ring of the β-lactam antibiotic and inactivate them. This issue is a threat for human health and one strategy to overcome this situation is co-administration of β-lactam antibiotics with an inhibitor. So far, no clinically available inhibitors of metallo β-lactamases (MBLs) reported and the clinically inhibitors of serine β-lactamase are useless for MBLs. Accordingly, finding a potent inhibitor of the MBLs being very important. In this study, imidazole derivatives primarily were synthesized and their inhibitory activity were measured. Later in silico binding model was used to predict the configuration and conformation of the ligands into the active site of enzyme. Two molecules demonstrated with IC50 of 39 μM and 46 μM against MBL (IMP-1).
- Khalili Arjomandi, Omid,Kavoosi, Mahboubeh,Adibi, Hadi
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- An efficient strategy for N-alkylation of benzimidazoles/imidazoles in SDS-aqueous basic medium and N-alkylation induced ring opening of benzimidazoles
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A sustainable route for the N-1 alkylation of imidazole and benzimidazole derivatives has been developed under volatile organic solvent free condition in alkaline water-SDS system. Incorporation of SDS in the reaction medium enhances the reaction rate by suppressing the solubility issue that arises for different substrates. This method provides high yield of the alkylated product in a shorter reaction time. For reactive alkyl halides reaction proceeds at ambient temperature whereas in the cases of less reactive alkyl halides require 55–60 °C to complete alkylation process. N-alkylation induced ring opening of the heterocyclic ring in benzimidazole derivatives to multifunctional aromatic compounds were noticed at 60 °C when more than two equivalents of alkyl halide was used.
- Chakraborty, Ankita,Debnath, Sudipto,Ghosh, Tanmoy,Maiti, Dilip K.,Majumdar, Swapan
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p. 5932 - 5941
(2018/09/18)
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- PALLADIUM PINCER COMPLEX OF NORMAL AND ABNORMAL CARBENE, PREPARATION METHOD FOR THE SAME AND USES THEREOF
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Palladium pincer complexes of both normal and abnormal carbene and preparation methods thereof are disclosed. Furthermore, uses of palladium pincer complexes of normal and abnormal carbene and pharmaceutical applications thereof are disclosed. Palladium pincer complex of normal and abnormal carbene are useful catalysts for C-C coupling reaction and therapeutic drugs for inhibiting tumor cell proliferation.
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Paragraph 0034; 0035
(2016/10/08)
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- Syntheses and QSAR studies of benzylimidazole derivatives and benzylcarbazole as potential aromatase inhibitors
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In this study, in order to explore new structures and chemical entities as aromatase inhibitors, benzylcarbazole, 12 benzylimidazole derivatives with different substituents on both phenyl and imidazole rings were synthesized and their aromatase inhibitory were evaluated with fluorescent substrate detection method. The results showed that the compounds with carboxyl and ester groups in phenyl ring show better inhibitory activity. The introduction of alkyl groups in imidazole may improve the aromatase inhibitory activity. Most of the compounds were more potent than aminoglutethimide and tamoxifen. 2-[2-{(2-ethyl-4-methyl- 1H-imidazol-1-yl)methyl}phenyl]acetic acid and benzylcarbazole have the highest bioactivities with IC50 values of 6.19 μM and 2.72 μM respectively. A meaningful QSAR model with LOF = 0.00359, R2 = 0.9914, Adj-R 2 = 0.9853, R2cv = 0.9639, F = 161.8, was constructed with genetic functional algorithm using discovery studio 2.1 package.
- Dai,Xiao,Wang,Wei,Zhang,Ma,Zheng,Hou,Zhang
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p. 2381 - 2388
(2014/06/09)
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- Gas-phase chemistry of benzyl cations in dissociation of N-Benzylammonium and N-benzyliminium ions studied by mass spectrometry
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In this study, the fragmentation reactions of various N-benzylammonium and N-benzyliminium ions were investigated by electrospray ionization mass spectrometry. In general, the dissociation of N-benzylated cations generates benzyl cations easily. Formation of ion/neutral complex intermediates consisting of the benzyl cations and the neutral fragments was observed. The intra-complex reactions included electrophilic aromatic substitution, hydride transfer, electron transfer, proton transfer, and nucleophilic aromatic substitution. These five types of reactions almost covered all the potential reactivities of benzyl cations in chemical reactions. Benzyl cations are well-known as Lewis acid and electrophile in reactions, but the present study showed that the gas-phase reactivities of some suitably ring-substituted benzyl cations were far richer. The 4-methylbenzyl cation was found to react as a Bronsted acid, benzyl cations bearing a strong electron-withdrawing group were found to react as electron acceptors, and parahalogen- substituted benzyl cations could react as substrates for nucleophilic attack at the phenyl ring. The reactions of benzyl cations were also related to the neutral counterparts. For example, in electron transfer reaction, the neutral counterpart should have low ionization energy and in nucleophilic aromatic substitution reaction, the neutral counterpart should be piperazine or analogues. This study provided a panoramic view of the reactions of benzyl cations with neutral N-containing species in the gas phase. American Society for Mass Spectrometry, 2012.
- Chai, Yunfeng,Wang, Lin,Sun, Hezhi,Guo, Cheng,Pan, Yuanjiang
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experimental part
p. 823 - 833
(2012/09/07)
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- Lithiation of 1-Benzylimidazole. A Hypothesis on the Regioselectivity of the Electrophilic Attacks on the Lithiated Species
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Sequential lithiations of 1-benzylimidazole, 1, and of 1-benzyl-1,2,4-triazole,2, followed by treatment with electrophiles others than alkyl halides result in reactions at C-2.However, benzyl halides and, to a certain extent, iodomethane react at the N-benzyl carbon atom.An explanatory hypothesis based on steric ortho effects is advanced.
- Moreno-Manas, M.,Bassa, J.,Llado, N.,Pleixats, R.
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p. 673 - 678
(2007/10/02)
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- A One Step Synthesis of 4-Substituted Imidazoles. An Important Observation When N-Alkylating Imidazoles
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Imidazoles substituted in the 2-position with methyl, 1e, phenyl, 1a, 2-imidazole, 1b-d, or t-butyldiphenylsilyl, 1f, react with soft electrophiles 2 to give modest yields of 4(5)-C-alkylated-imidazoles 3 and N-alkylated products 5.These two products are readily separated by flash chromatography.
- Whitten, Jeffrey P.,Matthews, Donald P.,McCarthy, James R.,Barbuch, Robert J.
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p. 1845 - 1847
(2007/10/02)
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- RAPID DEBENZYLATION OF N-BENZYLAMINO DERIVATIVES TO AMINO-DERIVATIVES USING AMMONIUM FORMATE AS CATALYTIC HYDROGEN TRANSFER AGENT
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Various N-benzyl derivatives of amino acids and amines were deprotected to the corresponding free amino acids and amines using ammonium formate as the hydrogen source.
- Ram, Siya,Spicer, Leonard D.
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p. 515 - 516
(2007/10/02)
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- 2-(N-SUBSTITUTED GUANIDINO)-4-HETERO-ARYLTHIAZOLE ANTIULCER AGENTS
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2,4-Disubstituted thiazole compounds of the formula STR1 or a pharmaceutically acceptable acid addition salt thereof wherein X is NH and Y is CH or N, orX is S and Y is CH;R 1 is certain straight or branched chain alkyl groups, (R 3) 2 C 6 H 3, or (R 3) 2 Ar(CH 2) n where n is an integer from 1 to 4, R 3 is H or certain substituent groups and Ar is phenylene, naphthalene or the residue of certain heteroaromatic groups; R 2 is H or (C 1-C 4)alkyl; or R 1 and R 2 taken together with the nitrogen atom to which they are attached form certain heterocyclic groups; and R 4 is H, (C 1-C 5)alkyl, NH 2 or CH 2 OH; a method for their use in treatment of gastric ulcers in mammals and pharmaceutical compositions containing said compounds.
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- 2,5-Dilithiation of N-Protected Imidazoles. Syntheses of 2,5-Disubstituted Derivatives of 1-Methoxymethyl-, 1-Triphenylmethyl-, and 1-(N,N-Dimethylsulphonamido)-imidazole
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The conditions previously established for the dilithiation of 1-methylimidazole are shown to be applicable to 1-methoxymethyl- and 1-triphenylmethyl-imidazole allowing good-yielding syntheses of 1,2,5-trisubstituted imidazole derivatives.The suitability of the 1-substituted (and of other groups) for the N-protection of imidazoles in dilithiation experiments is discussed and the use of the N,N-dimethylsulphamoyl protecting group is proposed. 1-Sulphamoylimidazole undergoes mono- and 2,5-di-lithiation quantitatively at low temperatures and in short reaction times.The results of work-up of the 2,5-dilithio intermediate with 1 mol equiv. of iodomethane or dimethyl sulphate indicate selectivity in favour of reaction at the 5-position.
- Chadwick, Derek J.,Ngochindo, Raphael I.
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p. 481 - 486
(2007/10/02)
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- Imidazole-isocyanuric acid adducts
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An imidazole-isocyanuric acid adduct having the following formula is disclosed: STR1 wherein R1 is a member selected from the group consisting of a hydrogen atom, a β-cyanoethyl group and a β-[3,5-diamino-s-triazinyl-(1)]-ethyl group, R2 stands for a monovalent hydrocarbon group having up to 17 carbon atoms, R3 is a member selected from the group consisting of a hydrogen atom and an alkyl group having up to 4 carbon atoms, with the proviso that when R1 is a hydrogen atom, R2 is a methyl or phenyl group and R3 is a hydrogen atom and when R1 is a β-cyanoethyl group, R2 is a phenyl group and R3 is a hydrogen atom, and n is a number of from 0 to 2. This adduct has peculiar characteristics not possessed by ordinary salts. Namely, the adduct is stable in water, and it decomposes in a solvent or under heating. The adduct is valuable as a curing agent for epoxy resins, and it can be utilized for purification of imidazoles.
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